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A new approach for modeling and analysis of a transmission and driveline system is proposed. By considering the stiffness, damping and inertias, model equations based on lumped parameters can be created through standard Lagrangian Mechanics techniques. A sensitivity analysis method has then been proposed on the eigenspace of the system characteristic equation to reveal the dynamic nature of a transmission and driveline system. The relative sensitivity calculated can clearly show the vibration modes of the system and the key contributing components. The usefulness of the method is demonstrated through the GM 6-speed RWD transmission by analyzing the dynamic nature of the driveline system. The results can provide a fundamental explanation of the vibration issue experienced and the solution adopted for the transmission.

This paper describes the capabilities of a new two-motor plug-in hybrid-electric propulsion system developed for rear wheel drive. The PHEV system comprises a 2.0L turbocharged 4-cylinder direct-injected gasoline engine with the new hybrid transmission [1], a new traction power inverter module, a liquid-cooled lithium-ion battery pack, and on-board battery charger and 12V power converter module. The capability and features of the system components are described, and component performance and vehicle data are reported. The resulting propulsion system provides an excellent combination of electric-only driving, acceleration, and fuel economy.

The development of a repeatable dynamic rollover test methodology with meaningful occupant protection performance objectives has been a longstanding and unmet challenge. Numerous studies have identified the random and chaotic nature of rollover crashes, and the difficulty associated with simulating these events in a laboratory setting. Previous work addressed vehicle level testing attempting to simulate an entire rollover event but it was determined that this test methodology could not be used for development of occupant protection restraint performance objectives due to the unpredictable behavior of the vehicle during the entire rollover event. More recent efforts have focused on subsystem tests that simulate distinct phases of a rollover event, up to and including the first roof-to-ground impact.

Under the initiative of The United States Council for Automotive Research LLC (USCAR) [1], we have developed and run comprehensive friction tests of dual clutch transmission fluids (DCTFs). The focus of this study is to quantify the anti-shudder durability over a simulated oil life of 75,000 shifts. We have evaluated six DCT fluids, including 2 fluids with known field shudder performance. Six different tests were conducted using a DC motor-driven friction test machine (GK test bench): 1. Force Controlled Continuous Slip, 2. Dynamic Friction, 3. Speed controlled Acceleration-Deceleration, 4. Motor-torque controlled Acceleration-Deceleration, 5. Static Friction, and 6. Static Break-Away. The test fluids were aged (with the clutch system) on the test bench to create a realistic aging of the entire friction system simultaneously.

Magnesium alloys are not corrosion resistant in many applications and they require coating protection. In this study, we developed an electroless E-coating technique for magnesium alloys and discussed a cathodic E-coating deposition mechanism for the electroless E-coating process. This coating can be formed within a few seconds by dipping a magnesium alloy (i.e., AZ91D) in an E-coat bath without applying a current or voltage. The deposited electroless coat can offer good protection to the AZ91D magnesium alloy in 5 wt% NaCl corrosive solution as well as in a phosphating bath. The most interesting finding is that the electroless coating is not sensitive to local damage. No preferential corrosion attack occurred along the scratches made on the coating.

A new apparatus for testing modern safety belt systems was developed. The apparatus design, dynamic behavior and test procedure are described. A number of tests have been conducted using this apparatus. These tests allowed identification of key performance parameters of pretensioners and load limiting retractors which are relevant to occupant protection in a crash environment. Good test repeatability was observed, which allowed comparison of different safety belt designs. The apparatus may be used for better specification and verification of safety belt properties on a subsystem level as well as for the validation of CAE models of safety belts used in simulations of occupant response to crash events.

Biodiesel is a domestic, renewable fuel for diesel engines and is made from agricultural co-products such as soybean oil, rapeseed oil, palm oil and other natural oils. Biodiesel is a cleaner burning fuel that is biodegradable and non-toxic compared to petroleum diesel. Biodiesel has become a major alternative fuel for automotive applications and is critical for lowering US dependence on foreign oil and attain energy security. Vehicle manufacturers have developed new vehicle and diesel engine technologies compatible with B6-B20 biodiesel blends meeting ASTM D7467 specifications. Field warranty and validation tests have shown significant concerns with use of poor quality biodiesel fuels including fuel system deposits, engine oil deterioration, and efficiency loss of the after treatment system. Maintaining good quality of biodiesel is critical for success as a commercial fuel.

Refinements were made to a post-processing technique, termed the Thermal Stratification Analysis (TSA), that couples the mass fraction burned data to ignition timing predictions from the autoignition integral to calculate an apparent temperature distribution from an experimental HCCI data point. Specifically, the analysis is expanded to include all of the mass in the cylinder by fitting the unburned mass with an exponential function, characteristic of the wall-affected region. The analysis-derived temperature distributions are then validated in two ways. First, the output data from CFD simulations are processed with the Thermal Stratification Analysis and the calculated temperature distributions are compared to the known CFD distributions.

Heat treated cast aluminum components like engine blocks and cylinder heads can develop significant amount of residual stress and distortion particularly with water quench. To incorporate the influence of residual stress and distortion in cast aluminum product design, a rapid simulation approach has been developed based on artificial neural network and component geometry characteristics. Multilayer feed-forward artificial neural network (ANN) models were trained and verified using FEA residual stress and distortion predictions together with part geometry information such as curvature, maximum dihedral angle, topologic features including node's neighbors, as well as quench parameters like quench temperature and quench media.

As the number of fixed gear ratios in automatic transmissions continues to increase in the pursuit of powertrain system efficiency, particular consideration must continue to be focused on optimizing the design for shifting performance. This investigation focuses on the effect of shift time on the performance attributes of shift quality, durability, on schedule fuel consumption and enablers to further reduce shift time. A review of fundamental design features that enable reduced shift times in both planetary and dual clutch transmissions is presented along with key operating features of both the transmission and engine/prime mover. A lumped parameter metric is proposed to assess and compare the upshift controllability of new transmission architectures and powerflows using simple analysis. The durability of fast shift times during performance maneuvers are quantified through calculation of shifting clutch energy and power from analysis and form measurements on a powertrain dynamometer.

For the conventional 6 speed automatic transmission with engine stop-start powertrain, an electrically-driven auxiliary pump is implemented to maintain the transmission line pressure as required to lock-up the CB1234 clutch during engine auto-stop conditions. Upon releasing the brake pedal, the transmission engages into first gear with the objective to accelerate the vehicle in a responsive manner. In this study, a novel normally-engaged dual-piston clutch concept is designed to keep the CB1234 clutch locked-up during engine auto-stop conditions with the intention to eliminate the auxiliary pump without compromising vehicle performance. This dual piston clutch concept requires a relatively low line pressure to release the normally-engaged clutch when needed, thus, minimizing the hydraulic pumping work. To explore the functionality of this concept under a wide-open-throttle (WOT) auto-start transition, modeling and simulation of the normally-engaged dual-piston clutch is completed.

This work analyzes the lubricant supply to critical regions of needle roller bearing of an automatic transmission. The needle roller bearing is a critical component of an automatic transmission and it has several rotating cylindrical needle rollers that are having relative motion with inner surface of the pinion. Supply of lubricant to the needle roller bearings is very essential to prevent failure of the bearings due to frictional contact between rollers and inner surface of pinion. The supply of lubricant to the needle roller bearings depends on the location of oil supply hole. Lubricant supply to the needle roller bearings of an automatic transmission is studied using commercial 3D Computational Fluid Dynamics (CFD) software for different oil supply positions. CFD simulation is performed for the region between the pinion supply hole and end of the needle bearings including all needles. Lubricant is supplied to the needle bearing from the pinion pin oil supply hole.

The need to reduce fuel consumption and harmful pollutants from engines is an important task for automotive industry. It has led to technological advances in new engine design, such as engine downsizing. Due to the reduction of displacement, engine power output is reduced and thus its overall performance is limited. In order to increase torque and power, engines are typically boosted by turbochargers or superchargers. Meanwhile, the improvement on turbo design makes it possible to operate VGT (variable geometry turbocharger) at harsher exhaust environment for gasoline engines as well (e.g., with much higher exhaust temperature than that of diesel engines). This makes VGT related control problems more challenging and requires attention to protecting corresponding engine hardware during an entire engine life.

In the vehicle development process, one important step is to set a component performance target from the vehicle level performance. Conventional barrier-decoupler dash mats and floor trim underlayment systems typically provide sound transmission loss (STL) with minimal absorption. Thus the performance of such components can be relatively easily specified as either STL or Insertion Loss. Lightweight dissipative or multi-layered acoustic materials provide both STL and significant absorption. The net performance is a combination of two parameters instead of one. The target for such components needs to account for this combined effect, however different suppliers use unique formulations and manufacturing methods, so it is difficult and time consuming to judge one formulation against another. In this paper, a unique process is presented to set a component target as a combined effect of STL and absorption.

More Mg alloys are being considered for uses in the automotive industry. Since the corrosion performance of Mg alloy components in practical service environments is unknown, long term corrosion testing at automotive proving grounds will be an essential step before Mg alloy components can be implemented in vehicles. However, testing so many Mg alloy candidates for various parts is labor intensive for the corrosion engineers at the proving grounds. This report presents preliminary results in evaluating corrosion performance of Mg alloys based on rapid corrosion and electrochemical tests in the lab. In this study, four Mg alloy candidates for transmission cases and oil pans: AE44, AXJ530, MRI153M and MRI230D were tested in the lab and at General Motors Corporation Milford Proving Ground and their corrosion results were compared.

This paper will examine the various design and performance criteria for optimized internal heat exchanger performance as applied to R134a and HFO-1234yf systems. Factors that will be considered include pressure drop, heat transfer, length, internal surface area, the effect of oil in circulation, and how these factors impact the effectiveness of the heat exchanger. The paper describes the test facility used and test procedures applied. Furthermore, some design parameters for the internal heat exchanger will be recommended for application to each refrigerant.

Development of the next generation internal combustion engines and automatic transmissions for automotive applications is a mandatory powertrain engineering activity required now and in the coming years to meet forthcoming global emissions regulations. This paper details a preliminary investigation into possible synergies for fuel consumption reduction considering emerging automotive technologies integrated into the next generation combustion engine and automatic transmission architectures. A range of hypothetical gasoline engines were created and paired with a generalized set of step gear automatic transmissions designed to meet the performance requirements of high volume longitudinal full size truck application. These designs were then run through a design of experiments orthogonal array for prediction of fuel consumption on the WLTP test schedule and stand still acceleration to 100 kph.

This paper presents an overview of a four-year project focused on development of an integrated computational materials engineering (ICME) toolset for third generation advanced high-strength steels (3GAHSS). Following a brief look at ICME as an emerging discipline within the Materials Genome Initiative, technical tasks in the ICME project will be discussed. Specific aims of the individual tasks are multi-scale, microstructure-based material model development using state-of-the-art computational and experimental techniques, forming, toolset assembly, design optimization, integration and technical cost modeling. The integrated approach is initially illustrated using a 980MPa grade transformation induced plasticity (TRIP) steel, subject to a two-step quenching and partitioning (Q&P) heat treatment, as an example.

The impact of texture on r-value and its measurement in magnesium alloy sheets has been studied using digital image correlation and electron backscatter diffraction techniques. Two magnesium alloy sheets with distinct textures were used in the present study, namely, AZ31 with a strong basal texture and ZE21 with a randomized texture. It is well known that a conventionally processed AZ31 magnesium sheet has strong basal texture, necessitating contraction and double twinning to accommodate thinning strain. The strain distribution on the sheet surface evolves nonlinearly with strain, impacting the measured r-value. In particular, the normal approach to measuring r-value based on average strains over the gauge section leads to the erroneous conclusion that r-value increases with deformation. When the r-value is measured locally at any point inside or outside the neck, the r-value is shown to have a constant value of 3 for all strain values.

Today's sophisticated state-of-the-art powertrains with various intelligent control units (xCU) need to be calibrated and tested stand-alone as well as in interaction. Today the majority of this work is still carried out with prototype vehicles on test tracks. Moving prototype vehicle tests from the road into the lab is key in achieving shorter development times and saving development cost. This kind of frontloading requires a modular and powerful simulation of all vehicle components, test track, and driver in steady state and dynamic operation. The described HIL (Hardware In the Loop) high performance driveline dyno test bed uses driveline components and models from the engine all the way to the wheel ends. The test cell was built to do real time vehicle maneuvers and NVH testing. This test setup can emulate any road surface and grade and vehicle inertia including wheels and engine as close to reality as possible.